New thermosetting mixtures of polyisocyanates,weakly branched polyesters and polyoles

ABSTRACT

Heat-curable plasticised mixtures for the manufacture of moulding materials based on polyurethanes, containing (a) a polyisocyanate, (b) a slightly branched polyester possessing terminal hydroxyl groups and (c) a defined aromatic polycarboxylic acid hydroxyester containing at least one secondary hydroxyl group (for example a hydroxyester manufactured by reacting 1 mol of trimellitic anhydride and 1 mol of 1,2propanediol in a first stage, and further reaction with 2 mols of cresylglycid), with the mixture containing, per 1 equivalent of isocyanate group, 0.05 to 0.3 hydroxyl equivalents of the polyester (b) and 0.3 to 1.0 hydroxyl equivalents of the aromatic polycarboxylic acid hydroxyester (c). The mouldings obtained by hot curing of the moulding compositions are flexible, tough and impact-resistant, and these mechanical properties are largely independent of temperature; a transition to the soft rubberyelastic state only occurs above 150*C.

United-State's Patent 1 1 Lohse et al.

[ 1 NEW THERMOSE'I'I'ING NHXTURES OF POLYISOCYANATES, WEAKLY BRANCHEDPOLYESTERS AND POLYOLES [75] Inventors: Friedrich Lohse, OberwilBasel-Land; Rolf Schmid, Reinach Basel-Land; Hans Batzer, Arlesheim, allof Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

[22] Filed: May 24, 1972 [21] Appl. No.: 256,527

[30] Foreign Application Priority Data June 3, 1971 Switzerland 8116/71[52] US. Cl 260/47 CB, 117/161 KP, 260/37 R,

260/37 M, 260/75 AT, 260/75 NK, 260/75 NP [51] Int. C1...'C08g 22/12,C08g 22/24, C08g 22/44 58] Field of Search 260/75 NK, 75 NP, 75 AT,

[56] References Cited UNITED'STATES PATENTS v 3,674,746 7/1972 Lohse eta1. .f. 260/75 .NP

[1111 3,821,165 [451 June 28, 1974 3,718,623 2/1973 Lohse et a1. 260/75NP Primary Examiner-Lester L. Lee

[ 5 7 ABSTRACT Heat-curable plasticised mixtures for the manufacture ofmoulding materials based on polyurethanes, containing (a) apolyisocyanate. (b) a slightly branched .polyester possessing terminalhydroxyl groups and (c) hydroxyl equivalents of the aromaticpolycarboxylic I acid hydroxyester (c). The mouldings obtained by hotcuring of the moulding compositions are flexible,-

tough and impact-resistant, and these mechanical properties are largelyindependent of temperature; a transition to the soft rubbery-elasticstate only occurs 'above 150C.

9 Claims, NoDrawings Lohse et a1. 260/75 NP -1 2 v NEW THERMOSETTINGMIXTURES OF wherein A represents an x-valent, weakly branchedPOLYISOCYANATES, WEAKLY BRANCHED long-chain polyester radical in whichalkylene and/or POLYESTERS AND POLYOLES alkenylene chains alternate withcarboxylic ester groups, and having a molecular weight of about 750 toIt is known that by reacting polyisocyanates with aliabout 10,000,preferably from 1,200 to 5,000, and x phatic polyesters which possess OHterminal groups it represents the um 3 Or pr erab y 4, and an ispossible to manufacture flexible moulded articles aromaticpolycarboxylic hydroxy ester which possesses which have a high degree offlexibility at room temperat least one secondary hydroxyl group and hasthe forature. However, such moulded articles become easily "1 1%. I

Rilll Ra llbnlun R!!! Rail C-O7CHC\ ii Ri 0 Ri' 11-1 (11) deformed andalready at slightly elevated temperature wherein R R R Rf, R R R and Reach still possess only slight strength. It was possible to imrepresenta hydrogen atom or a methyl group, or R prove the strenght at elevatedtemperature by the synand R or R, and R or R," and R or R, and R thesisof polymers which contain crystalline zones. together representabivalentaliphatic or cycloaliphatic These elastomeric polymers partly possessarelatively radical which is necessary to complete a ring, R R highstrenght at higher temperatures, in particular after R and R3," eachrepresent a hydrogen atom or an aliprior stretching. However, themoulded articles have a phatic, cycloaliphatic, araliphatic, aromatic orheterolow E-module and,particularly in the nonstretched stacyclicmonovalent radical which is unsubstituted or te, become easily deformed.As a rule they are fusible substituted or interrupted by oxygen atoms,and at least under heat and cannot be processed by the casting Or one ofthe radicals R R R or R represents such impregnating process. Moreover,the permanent deforan aliphatic, cycloaliphatic, araliphatic, aromaticor mation (stretching) is disadvantageous. heterocyclic radical, Zrepresents an alkylene radical The discovery has now been made that by.reacting 40 containing from two to three carbon atoms, m polyisocyanates(l) with aliphatic, slightly branched represents 0 or I and n and prepresent 1 or 2, and in polyesters which possess OH terminal groups (2)and the curable mixture for every 1 equivalent of isocyaspeciallystructured polyoles (3), flexible, tough, imnate group of thepolyisocyanate (1) there is present in pact resistant moulded articlesare obtained whose meeach case 0.3 to 1.0 equivalent of hydroxyl groupsof chanical properties are very largely independent of 5 the aromaticpolycarboxylic acid ester which contains temperature. The mouldedarticles in general have a hydroxyl groups (3) and in each case 0.02 to0.5, prefgood elasticity and good dimensional stability towards erably0.05 to 0.3 equivalent of hydroxyl groups of the deformation up torelatively high stresses. They are inpolyester (2). fusible and changeinto the soft rubbery-elastic state Instead of theindividualcomponents(l)and(2), the only at high temperatures, in mostcases only from curable mixtures according to the invention may alsoabove 150C. The moulded articles are amorphous, in contain a prereactedaddition product of the polyisocygeneral display no permanentdeformation and also no anate (l) and the polyester (2), in which casethere iscrystallisation skrinkage upon cooling. These factors used forthe adduct formation in each case, as indicated open up whole newperspectives for the industrial aphereinbefore, for every 1 equivalentof isocyanate plication of the new flexible polyurethane resin mixgroup0.02 to 0.5 equivalent of hydroxyl groups of the tures, particularly inthe field of casting, impregnating polyester.

and laminating resins, of foam plastics, bonding agents, In place of theindividual components (1) and (2), tool resins and moulding materials.the curable mixtures according to the invention may The presentinvention therefore relates to thermosetalso contain a prereactedaddition product of the 'polyting, plasticised mixtures based onpolyisocyanates, isocyanate (l) and the polyester (2), there being usedweakly branched polyesters and polyoles, which are for the adductformation in each case 0.02 to 0.5 equivsuitable as casting,impregnating and laminating resins alent of hydroxyl groups of thepolyester for every 1 and as bonding agents and moulding materials,which equivalent of isocyanate group, as indicated hereinbemixturescontain (1) a polyisocyanate containing on fore.

, average more than one isocyanate group in the mole- In the curablemixtures according to the invention,

cule; (2) a weakly branched polyester which possesses there may be usedas polyisocyanates basically all terminal hydroxy groups and correspondsto the genknown types which are compatible with the compoeral formula vv nents (2) and (3). Polyisocyanates, chiefly diisocya- A (OH), nates,of the aliphatic, cycloaliphatic, araliphatic, aro- (I) matic andheterocyclic series are suitable.

As examples there may be cited: ethylene diisocyanate, trimethylenediisocyanate, diisocyanates of the formula OCN-Y-NCO, wherein Arepresents the hydrocarbon radical of an optionally hydrogenateddimerised fatty alcohol; toluylenediisocyanate-(2,4),toluylene-diisocyanate-(2,6) or industrial mixtures thereof;diphenylmethane-4,4'- diisocyanate, 3,3-dimethyl-bipheny F4,4-diisocyanate, 3,3'-dimethoxy, 4,4-biphenyldiisocyanate,3,3-dichloro-biphenyl-4,4-diisocyanate, 4,4'-biphenyl-diisocyanate,diphenyldimethylmethane-4,4'-diisocyanate, p.p-bibenzyl-diisocyanate,phenylene-l ,4-diisocyanate, phenylenel ,3- diisocyanate, 2 ,3 ,5,6-tetramethyl-p-phenylenediisocyanate; the addition products of 2 molesof toluylene-2,4-diisocyanate with 1 mole of a glycol, or of 3 moles oftoluylene-2,4-diisocyanate with 1 mole of a triol, such as1,1,l-trimethylolpropane, whereby ideally a trifunctional, aromaticisocyanurate containing urethane groups is formed, also thecorresponding addition products of 2 moles of lsophorondiisocyanat with1 mole of a glycol.

The use of diisocyanates of the cycloaliphatic, cycloaliphatic-aliphaticor araliphatic series is preferred, for example:cyclopentylene-diisocyanate-l,3, cyclohexylene-diisocyanatc( 1,4), 1,3)or 1,2), hexahydrotoluylene-diisocyanatc-(2,4) or -(2,6), 3,5,5-trimcthyl-3-isocyanatomcthyl-cyclohexaneisocyanate- 1(=lsophoron-diisocyanate), dicyclohexylmethane-diisocyanate-(4,4), mandp-xylylene-oz, a-diisocyanate.

Preferred diisocyanates are also those of the heterocyclic-aliphaticseries, as examples of which there may be cited:

isocyanatopropyl)-5-methyl-5-ethyl-hydantoin, 1,3-di-(y-isocyanatopropyl )-5-ethyl-hydantoin. 1,3-di-(yisocyanatopropyl )-5-propyl-hydantoin, 1,3-di-(yisocyanatopropyl )-5-isopropy1-hydantoin,1,3-di-(yisocyanatopropyl)- 1 ,3-diazaspiro-(4,4)-nonane-2,4- dione andl,3-di-(y-isocyanatopropyl)- l ,3-diaza-spiro- (4,5 )-decane-2,4-dione,l,3-di-( y-isocyanatopropyl 5,S-dimethyl-5,6-dihydrouracil andl,3-di-('yisocyanatopropyl )-6-methyl-5,6-dihydr0uracil; 1,1-methylene-bis-( 3-y-isocyanatopropylhydantoin 1,1- methylene-bis-(3-y-isocyanatopropyl-5,5- dimethylhydantoin; 1,l -methylenebis-(3-yisocyanatopropyl-S-methyl-S-ethylhydantoin); bis-( 1'-y-i'socyanatopropylhydantoinyl-3l-methane; 1,2-bisl'-y-isocyanat0propyl-5 ',5-dimethylhydantoinyl-3)- ethane; l,4-bis-( l-y-isocyanatopropyl-5'-methyl-5 ethyl-hydantoinyl-3)-butane; l,6-bis-( l-yisocyanatopropyl-S -isopropylhydantoinyl-3 )-hexane; l,l2-bis-( l-y-isocyanatopropyl-5 ,5 pentamethylenehydantoinyl-3)-dodecane andB,B-bis-( l -y-isocyanatopropyl-5 ,5'-dimethylhydantoinyl- 3)-diethylether.

The long chain polyesters containing terminal hydroxyl groups which areused for the manufacture of the curable mixtures according to theinvention must be relatively weakly branched; Such polyesters areobtained by known methods by the polycondensation of aliphaticdicarboxylic acids with aliphatic diols in the appropriate molecularratio and in the presence of a polyfunctional starting molecule whicheffects the 4 branching (a trior tetravalent polyol or trior tetravalentpolycarboxylic acid) or by the polyaddition of several moles of alactone with 1 mole of a trior tetravalent polyol. The chain of suchpolyesters is built up by the recurring structural element whichconsists of an alkylene or alkenylene group and a carboxylic acid estergroup and should amount to 90 to 98 molar percent in the polyestermolecule, whereas the difference from 100 molar percent is attributableto the polyfunctional starting molecule responsible for the branching.Moreover, the average molecular size of the polyesters must lie withincertain limits (molecular weight about 750 to about 10,000).

As aliphatic dicarboxylic acids which may be preferably used for thesynthesis of such polyesters there may be cited: succinic acid, glutaricacid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacicacid, nonanedicarboxylic acid, decanedicarboxylic acid,undecanedicarboxylic acid, dodecanedicarboxylic acid, allylsuccinicacid, dodecylsuccinic acid, dodecenylsuccinic acid.

As aliphatic diols which may be preferably used for the synthesis of theinstant polyesters there may be mentioned: ethylene glycol,1,3-propanediol, 1,4- butane diol, 1,5-pentane diol, neopentyl glycol,1,6- hexane diol, 1,7-heptane diol, 1,8-octane diol, 1,9- nonane diol,1,10-decane diol, 1,1 l-undecane diol,

1,12-dodecane diol, l,6-dihydroxy-2,2,4- trimethylhexane,1,6-dihydroxy-2,4,4-trimethylhexane.

(III) wherein X represents the hydrocarbon radical of an aliphaticdicarboxylic acid obtained by splitting off the carboxyl groups and Xrepresents the hydrocarbon radical of an aliphatic diol obtained bysplitting off the hydroxyl groups, D represents .the hydrocarbon radicalof a'y-valent aliphatic or cycloaliphatic polyalcohol obtained bysplitting off the hydroxyl groups, y represents 3 or 4, preferably 3,and the integer 2, which indicates .the formula D (COOH),,, wherein D isthe y-valent hydrocarbon radical of a polycarboxylic acid containing ycarboxyl groups (y as a rule 3 or 4). In this case, 1 mole of the atleast trivalent polycarboxylic acid must be reacted in each case with(y' z) moles of an aliphatic 'dicarboxylic acid and y(z+l) moles of analiphatic diol.

The thus obtained polyesters may be illustrated by the general formula DL CO 0 -Xi0COX1CO0-X; O TH:L

wherein X and X have the same meanings as in formula III, D representsthe hydrocarbon radical of a y-, valent aliphatic, cycloaliphatic oraromatic polycarboxylic acid is obtained by splitting off the carboxylgroups, y represents 3 or 4, preferably 3, and the'integer 2, whichindicates the average number of the structural elements COX,-COOX -O perlinear branched chain, is so chosen that the average molecular weight ofthe polyester is about 750 to about 10,000.

Polyvalent polycarboxylic acids of the formula D (COOH),, which are usedas starting molecules are, for example, trimellitic acid, trimesic acid,citric acid, tricarballylic acid, .malic acid and butane-1,2,4-tricarboxylic acid.

It is, of course, also possible to manufacture polyesters by condensingmixtures of various dicarboxylic acids with mixtures of various diols,always providing that. the above postulated conditions with regard tothe molecular weight in respect of the resulting polyester are observed.

Also suitable for the purposes of the invention are the polyesters whichare obtainable by the addition of z moles of a lactone to 1 mole of ay-valent polyol in accordance with'the reaction equation "Llll wherein Xrepresents an alkylene chain containing at least 4 and preferably atleast five carbon atoms, X, represents an aliphatic hydrocarbon radicalwhich can be obtained by splitting off the hydroxyl groups, y represents3 or 4, preferably 3, and the integer 2, which indicates the averagenumber of structural elements per linear branched chain, is so chosenthat the average can be manufactured by esterifying abenzenetricarboxylic acid or benzenetetracarboxylic acid, such-astrimesic acid, hemimellitic acid and, in particular, trimellitic orpyromellitic acid, or the functional deriva tives of thesepolycarboxylic acids, particuarly the anhydrides, with a monoepoxide ofthe formula or a glycol of the formula HG m ym MIXER in which processthe esterification is carried out in a single step or in several steps,and R R and R have the same meanings as in formula (II), but with theproviso that R may not be hydrogen if the esterification is carried outin a single step with a unitary compound of the formula (VI) or (VII).On the other hand, it is possible to use a compound, in which R, is ahydrogen atom, in a two-step process, wherein in one step at least onecarboxyl group of the benzenepolycarboxylic acid is esterified with amonoepoxide (VI) or a glycol (VII), in which R is different fromhydrogen.

The synthesis of the polycarboxylic acid ester (3) starting frombenzenepolycarboxylic acid and monoepoxide (VI) proceeds according tothe following reac- Suitable monoepoxides (VI) for the manufacture ofthe esters which contain hydroxyl groups are in particular: propeneoxide, 1,2-epoxybutan, butane-2,3-epoxide, pentane-2 ,3-epoxide,cyclohexene oxide, styrene oxide, phenylglycidyl ether, cresylglycidylether, N-glycidyl-oxazolidin-Z-one, 3(N)-glycidyl-5,S-dimethylhydantoin.

In a multi-step esterification of the carboxyl groups it is alsopossible to use ethylene oxide, but in this case at least one of thecarboxyl groups must be esterified with a monoepoxide which is differentfrom ethylene oxide If an anhydride of benzenepolycarboxylic acid isused as starting material, it can be advantageous to carry out theesterification in a first step with 1 mole of aglycol of the formula(VII) for every 1 anhydride group, in the process of which the anhydridegroups are split off and half esters with free carboxyl groups areformed. For trimellitic anhydride, this first step has for example thefollowing reaction scheme:

00 Nooo- 0+m-on-o OH on R 00 oooH HOOC- i on B8 coo-pH-b Theesterification of the still free carboxyl groups of the resulting halfester is then carried out advantageously by reaction with the necessaryequivalent amount of a monoepoxide of the formula (VI), in the processof which the monoepoxide chosen for the esterification of the secondstep may be derived from a glycol which is the same as, or differentfrom, the glycol used in the first esterification step.

As examples of glycols (VII) there may be cited: 1 ,2-

propane diol, 1,2-butane diol; it is also possible to use ethyleneglycol for a partial esterification if in an additional step for theesterification another glycol or a monoepoxide which is different fromethylene oxide is used.

The benzenetrior tetracarboxylic hydroxy esters of the formula (11)contain preferably at least two secondary hydroxyl groups. The aromaticpolycarboxylic acid esters (3) of the formula (ll), wherein n 2, can bemanufactured by reacting 2 moles of the monoanhydride of abenzenetricarboxylic acid, in particular e.g., trimellitic anhydride,with 1 mole of a glycol containing two or three carbon atoms, such asethylene glycol, 1,2- propane diol or 1,3-propane diol, in a first step,for example according to the reaction equation and subsequentlyesterifying the resulting tetracarboxylic acid with 4 moles of anepoxide of the formula (VI).

The curable mixtures according to the invention are suitable primarilyas casting resins, impreganting resins and bonding agents. A furtherindustrially useful field of application is the manufacture of flexiblefoam plas- '(2), in which case a larger excess of isocyanate is used forthis prereaction. Such an adduct, which still contains free isocyanategroups or an amount of nonreacted polyisocyanate, may be used in thecurable mixture in place ofthe non-prereacted individual components (1)and (2). As a rule, moulded. articles possessing analogous propertiesare obtained with such adducts. However, curable mixtures based on suchadducts have a high viscosity and are therefore less suitable as castingor impregnating resins. But they can be used with advantage as mouldingmaterials, laminating resins, bonding agents or in the field of surfaceprotection, e.g. as powder for whirl sintering or resin for paints andvarnishes, since they display less sensitivity to moisture.

The curing of the curable mixtures according to the invention tomoulding materials takes place in known manner, as a rule 'in thetemperature range from conventional additives or modifiers, such asfillers,

dyes, pigments, flame retardants, mould lubricants etc. As extenders andfillers there may be used, for example, glass fibres, carbon fibres,boron fibres, mica, powdered quartz, cellulose, calcined china clay,ground do lomite, colloidal silica with a large specific surface(=silicic acid aerogel, registered trademark AEROSlL) or metal powder,such as aluminium powder.

The cured moulded articles are disinguished by high flexibility (highdeflection at break) and impact strength. The shear modulus at roomtemperature has been distinctly lowered by the plasticising. Themoulding materials have, however, a surprisingly hightensile strength;their electrial and in particular mechanical properties change only veryslightly with temperature, so that the moulded articles are stillclearly flexible at temperatures below 20C, but at temperatures up to100C and partly up to above 160C, still display good strengths. Themodulus of shear values measured at various temperatures, e.g. accordingto DIN 53 445, provide a valuable point of reference on the trend of thephysical properties as function of the temperature.

In the following Examples the percentages are by weight.

The following long-chain polyesters containing hy- I droxyl groups andbenzenepolycarboxylic acid esters containing hydroxyl groups were usedfor the manufacture described in the Examples of plasticised, curablemixtures:

Manufacture of long-chain, slightly branched polyesters Polyester A 24.0g (0.2 mole) of trimethylolethane were mixed with 484.8 g (2.4 moles)'ofsebacic acid and 283.2 g (2.4 moles) of hexane-1,6-diol (correspondingto a molar ratio of 1:12:12) and the mixture was heated under a nitrogenatmosphere to 170C. The reaction mixture was then allowed to react for 2hours at 170C, for 3 hours at 190C, for 2 hours at 210C and for 15.5hours at 230C. In the process, 76.7 g of water (theory:84.4 g) weresplitt off. The reaction products was a light brown, hard substance withan acid equivalent weight of 19,600, a hydroxy equivalent weight of 922(theoryzl 176) and a melting point of 60C (measured with a differentialscanning calorimeter);

Polyester B 48.0 g (0.4 mole) of trimethylolethane were mixed with 566.4g (4.8 moles) or'succinic acid and 337.6 g (4.8 moles 13.5 percent) ofethylene glycol (corresponding to a molar ratio of 1:12:12) and themixture was heated to 160C under a nitrogen atmosphere. The

be mixed prior to the curing in any phase with other reaction mixturewas then allowed to react for 4 hours at C, for 16 hours at C and for 15hours at 180C under 50 mm Hg, in the course of which a light brownprosuct formed which is crystalline at room temperature and with an acidequivalent weight of 90,000 and a hydroxyl equivalent weight of 718(theory:616). Polyester C 5.36 g (0.04 mole) of hexane-1 ,2,6- triolwere mixed with 70.08 g (0.48 mole) of adipic acid and 31.3 g (0.48 mole5 percent) of ethylene glycol (corresponding to a molar ratio of1:12:12) and the mixture was heated to 160C under a nitrogen atmosphere.The reaction mixture was then allowed to react for'35 hours at 160C andfor 17 hours at 160C under 10 mm Hg. In the process, 8.8 g of water weresplit off. The reaction product was a grey crystalline substance with anacid equivalent weight of 55 85, a hydroxyl equivalent weight of 1108(theory: 733) and a melting point of 9 36C (measured with a differentialscanning calorimeter).

Polyester D 9.2 g (0.1 mole) of glycerol were mixed with 278.1 g (30moles 3 percent excess) of butane-1,4-diol and 300.0 g (3.0 moles) ofsuccinic anhydride (corresponding to a molar ratio of 1:30:30), 05 ml ofpyridine was added thereto and the mixture heated to 160C under anitrogen atmosphere. The reaction mixture was then allowed to react for13 hours at 160C and for 73 hours at 160C under, mm Hg. in the process46 ml of water (theory:54 ml) were split off. The reaction product was alight brown crystalline substance with an acid equivalent weight of12,680, a hydroxyl equivalent weight of 1591 (theoryzl751) and a meltingpoint of l l 1C (measured with a differential scanning calorimeter).Manufacture of benzenepolycarboxylic hydroxy esters Tetrahydroxy ester 1from pyromellitic anhydride, propane-1,2,diol and cyclohexene oxide 76.0g (1.0 mole) of propane-1,2-diol were mixed with 109.0 g (0.5 mole) ofpyromellitic, anhydride and 0.7 ml of N-benzyl-dimethylamine and themixture was dissolved (time required about 15 minutes). Then 138.0 g 1.0mole 41 percent excess) of cyclohexene oxide were added dropwise withinminutes at the same temperature. The reaction mixture was then allowedto react for 12 hours at 130C at room temperature. At room temperaturethe reaction product was a brown glass-like substance and had an acidequivalent weight of 17 13 and a hydroxyl equivalent weight of215(theory: 188). The reaction proceeds according to the followingTrihydroxy ester 11 from trimellitic anhydride, propanel,2-diol andcyclohexene oxide 266.0 g (3.5 moles) or propane-1,2-diol were treatedwith 2.0 ml of benzyldimethylamine and the mixture was added to 672.0 g(3.5 moles) of trimellitic anhydride. In the process a pastyreactionmixture forms which is heated to 130C and to which 960 g (7.0 moles 40percent excess) of percent cyclohexene. oxide are added dropwise overthecourse of 1 hour. During this process, increasing solution occurs ina weakly exo- 10 I therrnic reaction, but only after 48 hours at C doesa clear reaction solution result. I

The reaction solution is then freed from volatile con stituents at thesame temperature under a water jet vacuum.

The resulting product had a hydroxyl equivalent weight of 282 and anacid equivalent weight of 2500. It was in the form ofa brown glassysubstance. Processing Examples Sheets measuring X 135 X 4 mm weremanufactured to determine the flexural strength, deflection, impactstrength and water absorption; similar sheets, but with a thickness of 1mm, were manufactured for the tensile strenght test and the shearmodulus. The corresponding test specimens were prepared from the sheets;for the tensile strenght test, the test specimens No. 2 corresponding toISO R 527 were punched out with a well ground tool at about C.

EXAMPLE 1 172 g (0.8 OH equivalent) of tetrahydroxy ester I were stirredfor 1 hour at 130C and 12 mm Hg with 184 g (0.2 equivalent) of polyesterA. Under the same vacuum pressure, 87 g (1.0 equivalent) of an isomermixture of 2,4-toluylene-diisocyanate and 2,6- toluylene-diisocyanatewere then added dropwise in a ratio of 65:35 and with an isocyanatecontent of l 1.5 equivalents/kg. The mixture was poured into mouldspreheated to 100C and made from aluminium alloy treated with a siliconeresin varnish (registered trademark Anticorodal").After a heat treatmentfor 2 hours at 100C, bubble-free moulded articles with the followingproperties were obtained:

tensile strength according to ISO R 527 177 kg/cm elongation at breakaccording to ISO R 527 130 percent EXAMPLE 2 1 2.; I equivalent) f stahxtqzsxsstet was stirred for 1 hour at 130C and 12 mm Hg with'144 g(0.2 equivalent) of polyester B. Under the same vacuum pressure, 87 g(1.0 equivalent) of the diisocyanate used in Example 1 were addeddropwise and the mixture was poured into the moulds which were preheatedto 100C as in Example 1. After the heat treatment for 2 hours, mouldedarticles with the following properties were obtained:

tensile strength according to ISO R 527 820 kg/cm elongation at breakaccording to ISO R 527 5 percent EXAMPLE 3 elongation at break accordingto [SD R 527 percent l1 EXAMPLE 4 172 g (0.8 H equivalent) oftetrahydroxy ester 1 were stirred for 1 hour at 130C and 12 mm Hg wth319 g (0.2 equivalent) of polyester D. Under the same vac- 12 v whereinR R R R R R R and R each represent a hydrogen atom or a methyl group, orR and R or R and R or R and R or R and R2, together represent a bivalentcycloaliphatic radical uum Pressure, 112 g (1.0 equivalent) of 3,5,5- 5i f necessary to completearing R3trimethyl-3-isocyanato-methylcyclohexane-isocyanate R3 i reprgsem ahydrogen zlltom or an alkyl ,wlth l) (lsophorondiisocyanat) were thenadded dropfi to gh m an at east s h mem' wise and the mixture was pouredinto the moulds prei 3 R3 repr.eSemS an up i Cycle heated to 100C as inExample L After the heat Heap al1phat1c, aral1phat1c, aromatlc orheterocychc rad1cal, ment for 2 hours, moulded articles with thefollowing z 18 an alkylene radlcal contammg from 2 to 3 carbonproperties were Obtained: atoms, m represents 0 to 1 and n and 1represent 1 or tensile strength according to R 527 2194 kglcmg 2, and 1nthe curable m1xture for every 1 equlvalent of isocyanate group of thepolyisocyanate (1) there is elongation at break according to rso R 527350 present f of percent 5 groups of the aromat1c polycarboxyhc ac1dester wh1ch contains hydroxyl groups (3) and in each case 0.02 toEXAMPLE 5 0.5 equivalent of hydroxyl groups of the polyester (2).

18.4 g (0.02 equivalent) of polyester A and 22.6 g I 1 (0.08 equivalent)of trihydroxy ester 11 were mixed at A composltlon dcfordmg to 61mm l hC. The mixture was briefly evacuated and then '1 1.2 20 cqmpollem (I) ia dilsocyanate of the cycloahphanc' g (0.10 equivalent) ofisophorondiisocyanat were g i or arailphatlc g l 2 h h added thereto.The mixture was briefly evacuated once composition accor. mg to c i werem t 6 more at about 60C and poured into the moulds precomponent s355'mmethyl'3'lsocyanatomethyl' heated to C as in Example 1. After aheat treat- 9q i. ment for 1 hour at C and 1 hour at C, moulded 5 A F' Eclam wherem articles with the following Properties were obtained:figmponent g i SW of 244Oluylene' tensile strength according to R 527285 k /cm socyanate i 5. A composltion accordmg to cla1m 1, wherem thecomponent (2) is a slightly branched polyeser which a g gi accordmg to R527 285 percent 30 contains hydroxyl groups and has the generalformula 1. A heat-curable composition of matter which comprl ID-EO(CO--X,CO-O-X -O),H],, 1. an 1socyanate containmg on average morethan one isocyanate group in the molecule; 35

2. a slightly branched polyester which possesses terh p f' h y j aq ofan minal hydroxy groups and corresponds to the al1phat1c dlcarboxylicac1d obtamed by splmng off the era] f carboxyl groups and X representsthe hydrocarbon radical of an aliphatic diol obtained by separation of)r the hydroxyl groups, D represents the hydrocarbon I 4O radical of'ay-valent aliphatic or cycloaliphatic polyalwherein A represents anx-valent, slightly branched cohol obtained by splitting off the hydroxylgroups, y long chain polyester radical in which alkylene oralkerepresents 3 or 4 and the integer z, which indicates the nylenechains alternate with carboxylic ester groups, average number of thestructural elements -COX- .and having a molecular weight of about 750 toabout 4 CO--O---X --O--- per linear branched chain, is so 10,000 and .t'represents the number 3 or 4 and 5 chosen that the average molecularweight of the polyes- 3. an aromatic polycarboxylic acid hydroxy esterter is about 750 to about 10,000.

which possesses at least one secondary hydroxyl 6. A compositionaccording to claim 1, wherein the group and has the formula component(3) isa polyhydroxy ester of trimellitic acid I v 3,821,165 y whichcontains at least one secondary hydroxyl group 8. A compositionaccording to claim 1, wherein the and has the formula component (3) is apolyhydroxy ester of pyromellitic v acid which contains at least onesecondary hydroxy] group and has the formula R GOO(|3HC\ 5 In H R IKZ iC H R;- -iJH-0oc- 000- 11-0-41," ooo-oH-o--R," I

Y OH R7C-CH-OOC COO-C HC---R;

V V I V .n. R H 1 In wherein the symbols R'have the same meanings as inW claim 1. 1 wherein the symbols R have the same meanings as in 7. Acomposition according to claim 6, wherein the Claim 1. component (3) isthe trimellitic hydroxy ester of the 9. A composition according to claim8, wherein the formula 15 component (3) is the pyromellitic hydroxyester of the formula 0 0 o-cm- CPL-CH1 H cH.-c1r crr,-o o oo o o-cr,-cH-on, I 11 H o=0 C O 1 H0 000 000 0H 0 o 4 1 OH HO =l

2. A composition according to claim 1 wherein as the component (1) is adiisocyanate of the cycloaliphatic-aliphatic or araliphatic series.
 2. aslightly branched polyester which possesses terminal hydroxy groups andcorresponds to the general formula A-(OH)x wherein A represents anx-valent, slightly branched long chain polyester radical in whichalkylene or alkenylene chains alternate with carboxylic ester groups,and having a molecular weight of about 750 to about 10,000 and xrepresents the number 3 or 4 and
 3. an aromatic polycarboxylic acidhydroxy ester which possesses at least one secondary hydroxyl group andhas the formula
 3. A composition according to claim 2, wherein thecomponent (1) is3,5,5-trimethyl-3-isocyanatomethyl-cyclohexane-isocyanate-(1).
 4. Acomposition according to claim 2, wherein the component (1) is an isomermixture of 2,4-toluylene-diisocyanate and 2,6-toluylene-diisocyanate. 5.A composition according to claim 1, wherein the component (2) is aslightly branched polyeser which contains hydroxyl groups and has thegeneral formula D-O-(CO-X1-CO-O-X2-O-)z-H)y wherein X1 represents thehydrocarbon radical of an aliphatic dicarboxylic acid obtained byspliting off the carboxyl groups and X2 represents the hydrocarbonradical of an aliphatic diol obtained by separation of the hydroxylgroups, D represents the hydrocarbon radical of a y-valent aliphatic orcycloaliphatic polyalcohol obtained by splitting off the hydroxylgroups, y represents 3 or 4 and the integer z, which indicates theaverage number of the structural elements -CO-X1-CO-O-X2-O- per linearbranched chain, is so chosen that the average molecular weight of thepolyester is about 750 to about 10,000.
 6. A composition according toclaim 1, wherein the component (3) is a polyhydroxy ester of trimelliticacid which contains at least one secondary hydroxyl group and has theformula
 7. A composition according to claim 6, wherein the component (3)is the trimellitic hydroxy ester of the formula
 8. A compositionaccording to claim 1, wherein the component (3) is a polyhydroxy esterof pyromellitic acid which contains at least one secondary hydroxylgroup and has the formula
 9. A composition according to claim 8, whereinthe component (3) is the pyromellitic hydroxy ester of the formula